Where does “lau” come from?

lau (Malay) comes from Malay kalau, from Sanskrit काल, from Proto-Turkic kār, from Proto-Iranian karah — fold, of time (during which an action or event happens).

Ancestry of “lau”, step by step

StepLanguageWordMeaning
1Malaykalauif; as for; when
2Sanskritकालblack, dark blue; black, dark blue colour; pupil
3Proto-Turkickārsnow
4Proto-Iraniankarahfold, of time (during which an action or event happens)
Every word from Proto-Iranian karah →Every word from Proto-Turkic kār →Every word from Sanskrit काल →